|Publication number||US4736454 A|
|Application number||US 06/532,556|
|Publication date||Apr 5, 1988|
|Filing date||Sep 15, 1983|
|Priority date||Sep 15, 1983|
|Publication number||06532556, 532556, US 4736454 A, US 4736454A, US-A-4736454, US4736454 A, US4736454A|
|Inventors||Vincent A. Hirsch|
|Original Assignee||Ball Corporation|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (16), Non-Patent Citations (19), Referenced by (56), Classifications (19), Legal Events (5)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This invention relates to an integrated oscillator and antenna system formed in a thin conformable structure. Such structures have many useful applications but may be especially useful in doppler radar ranging systems as, for example, a component of a radio frequency proximity fuze for armaments.
The potential advantages of a proximity fuze r.f. front-end including a self-oscillating antenna system have been recognized for many years. Such advantages would include, for example, ease of fabrication, a reduced number of circuit components, high product yields, and low costs.
When designing antenna systems for doppler radars used in projectile or missile proximity fuzing, the typical conventional approach requires an antenna system with a 50 ohm output impedance. The oscillator is mounted on a circuit board on which a microstrip antenna system is printed. This configuration has several disadvantages:
Changes in the circuit board dielectric constant and variations in the etching techniques used to fabricate the microstrip antenna elements result in antenna resonant frequency shifts. This produces a suboptimal impedance match between the oscillator and antenna system. Maximum power at the desired frequencies is not radiated.
The hybrid oscillator must be mounted on the top or bottom side of the antenna. This results in a system which is not low profile and difficult to mount or dismount for repair.
Hybrid integrated circuit oscillators are generally expensive and not simple to fabricate.
One approach which has been used to produce an integrated oscillator and antenna system utilized a feedback loop between the antenna and oscillator. The antenna then becomes part of the primary frequency determining network. The major problem with this approach has been low operating efficiencies.
Oscillatennas fabricated in the past are believed to have had relatively low operating efficiencies and/or high l/f (flicker) noise and phase noise. Furthermore, the integration of a separate hybrid microwave integrated circuit (MIC) oscillator with an antenna, both having 50 ohm interface impedances for example, is costly and often does not provide optimum performance because of antenna resonant frequency variations due to material property tolerances or variations in the fabrication processes used to manufacture the antenna as noted above.
Some examples of prior art approaches to microwave integrated circuit (MIC) oscillator design are illustrated by the following:
U.S. Pat. No. 3,629,724--Shiga (1971)
U.S. Pat. No. 3,778,717--Okoshi et al (1973)
U.S. Pat. No. 3,986,153--Kuno et al (1976)
U.S. Pat. No. 4,034,313--Jones et al (1977)
U.S. Pat. No. 4,185,252--Gerlach (1980)
U.S. Pat. No. 4,331,940--Uwano (1982)
Japanese Patent No. 38,705--Takeda (1980)
Of this group, Okoshi et al is possibly the most pertinent for its teaching of a unified (and apparently conformal) integrated oscillator/antenna structure including a shaped single layer of conductive surfaces spaced from an underlying electrical conductive reference surface by a relatively thin dielectric layer. However, Okoshi et al teach only the use of a two-element active device (i.e., a Gunn diode) that is inherently quite inefficient. Furthermore, Okoshi et al teach the use of a separate resonator structure in addition to a radiator which itself comprises a small non-resonant slit in the middle of the resonator structure. Okoshi et al do not appear to teach how a three-element active device might be accommodated in such a thin conformal structure nor do they teach the use of a microstrip type radiator patch which, together with a transmission line, may directly provide the r.f. load impedance for the oscillator and maximize power output therefrom.
Of course, the microstrip antenna including its radiator and transmission line feed is by now a well known structure in and of itself. In its simplest form, the microstrip radiator patch may simply be a square or rectangular element fed at one of its edges by an integral microstrip transmission line. This shaped transmission line/radiator surface is typically supported a very short distance above a ground plane by a dielectric sheet or layer having a thickness substantially less than one-fourth wavelength at the intended operating frequency (e.g., typically on the order of one-tenth wavelength or less). The resonant dimension of such a radiating patch is typically chosen to be one-half wavelength thus providing a pair of radiating slots between opposed edges (e.g. transverse to the feedline) and the underlying ground plane. The transverse or non-resonant dimension of the radiator is typically chosen, at least in part, as a function of the desired relative radiated power. If the non-resonant dimension is on the order of one wavelength or more, then typically multiple feed points are provided (e.g., via a corporate-structure feed network). Such microstrip radiators may typically also be arrayed with corporate or other structures of microstrip feedlines integrally formed and connected therewith.
As will also be appreciated by those in the art, such a dual-slotted microstrip radiator provides a relatively high r.f. impedance at its outermost edge (e.g., on the order of 200-300 ohms) and various lower impedances internally to a region of minimum r.f. impedance near the center of the radiator element. Accordingly, impedance matching "notches" are typically cut into the edge of such a microstrip radiator so as to permit a matched impedance feedline connection when the feedline is integrally formed and connected with the radiator in a single shaped layer of conductive surfaces.
Such conventional shaped microstrip antenna structures are usually formed by photo-chemical etching processes similar to those used for the formation of printed circuit boards. The material used is typically a relatively thin dielectric sheet (e.g. PTFE) clad on both sides with a thin layer of conductive metal. One such cladded side typically forms a ground or reference surface while the other side is photo-chemically etched into a shaped conducting surface so as to form the microstrip radiator and interconnected transmission line structures. The thickness of the whole structure is typically on the order of only 1/32 inch.
Where three element or terminal active devices are to be used in an oscillator circuit, there are also relatively well known circuit design techniques for determining the optimum oscillator load impedance using "device line measurements" or "load-pull measurements" based on the known S-parameters of the active device. Typical prior art references teaching oscillator design techniques such as these are, for example:
1. J. Gonda, "Large Signal Transistor Oscillator Design", IEEE MTT-S International Microwave Symposium Digest, 1972, pp. 110-112.
2. Walter Wagner, "Oscillator Design by Device Line Measurement", Microwave Journal, Volume 22, pp. 43-48, February 1979.
3. Hewlett-Packard Application Note 95-1, "S-Parameter Techniques for Faster More Accurate Network Design", p. 10.
4. Dennis Poulin, "Load-Pull Measurements Help Meet Your Match", Microwaves, Volume 19, pp. 61-65 (November 1980).
5. Hewlett-Packard Application Note 975, "A4.3 GHz Oscillator Using the HXTR-4101 Bipolar Transistor".
6. Hewlett-Packard Application Note 981, "The Design of a 900 MHz Oscillator with the HXTR-3102".
7. Microwave Semiconductor Application Note TE-213, "GaAs FET Power Oscillators".
I have now discovered a novel integrated oscillator/microstrip antenna system using a three-element active device (e.g., a bipolar transistor or FET transistor) which permits the three-element active device to be physically integrated (i.e., both mechanically and electrically) onto a single layer of shaped or "printed" conductor which includes the microstrip antenna radiator together with associated feedlines, series resonant oscillator reactance elements and d.c. biasing circuits. The microstrip antenna radiator and its feedline are situated so as to directly provide the optimum oscillator load impedance needed to maximize its power output. The composite structure is formed on one side of a dielectric sheet opposite a ground or reference plane provided on the other side of the dielectric sheet. The result is a thin, lightweight, conformal and efficient oscillator/antenna assembly. Although the frequency and power range of the overall system is obviously constrained by the active device used, within that envelope of limits, the microstrip antenna and/or other microstrip "printed" circuit elements determine both the frequency and the power that will be radiated from the system.
By incorporating the antenna system as an integral part of the three-element active device oscillator on a printed circuit board and by utilizing the microstrip antenna to directly provide the oscillator load impedance (thereby determining the frequency and power of the radiated signal), a simple low cost overall system is provided. At the same time, the integrated oscillator and microstrip antenna system is low profile, conformal and does not provide so many fabrication difficulties as many of the prior art systems described above. Furthermore, for some applications (e.g., fuzing) it may be desirable for each unit to operate at a slightly different frequency so as to minimize jamming possibilities or probabilities. Typical circuit board dielectric constants and etching variations will produce oscillatennas with this desirable operating frequency spread.
This invention not only provides a desired conformal low profile system, it permits easy control of frequency and maximum radiated power as well as maximum operating efficiency. Depending upon the three-element active device involved, the invention may be used from relatively low frequencies to very high frequencies (e.g., greater than 26 GHz) while reducing the cost of fabrication by the use of only simple microstrip circuitry in addition to the active device itself.
A conventional receiver antenna and detector circuit can be incorporated with an oscillatenna to provide a complete low cost microwave integrated circuit doppler radar for a variety of different applications:
proximity fuzing on projectiles and missiles
vehicle speed monitoring
collison avoidance systems
expendable decoys for jamming enemy radars or communications
These as well as other objects and advantages of the invention will be better appreciated by careful study of the following detailed description of the presently preferred exemplary embodiments of this invention taken in conjunction with the accompanying drawings, of which:
FIG. 1 is a partially perspective but essentially plan view of an exemplary embodiment of an oscillatenna constructed in accordance with this invention;
FIG. 2 is an electrical schematic diagram of an equivalent lumped parameter electrical circuit for the exemplary embodiment of FIG. 1;
FIG. 3 is a Smith Chart depicting the manner in which the input impedance of the microstrip antenna at its feed point is transformed along the microstrip feedline to directly provide the optimum predetermined load impedance required for the oscillator of the embodiment depicted at FIGS. 1 and 2;
FIG. 4 is a view of an exemplary embodiment of this invention similar to that shown in FIG. 1 but including slight alterations (e.g., the use of a "notch" at the microstrip antenna feed point to assist in selecting the desired predetermined oscillator load impedance;
FIG. 5 is a simplified schematic diagram of the radio frequency circuit of the exemplary embodiments using a bipolar junction transistor; and
FIG. 6 is a schematic diagram similar to FIG. 5 but using a field effect transistor instead of a bipolar junction transistor as the three element active device.
The exemplary oscillatenna embodiment depicted in FIG. 1 is formed from a conventional PTFE dielectric sheet 3 cladded on one side with a conductive ground plane 4 and, initially, similarly cladded on the opposite (or topside as shown in FIG. 1) with a single layer conductive surface mechanically supported in a spaced relationship from the ground plane 4 by the dielectric sheet 3. Using conventional photo-chemical etching techniques, the top single layer conductive surface is formed into a shaped single layer of conductive surfaces 1, 2, 6, 7, 8, 9, 10, 11 and 12. As previously mentioned, the dielectric layer is of a thickness substantially less than one-fourth wavelength at the intended operating frequency of the system (e.g., on the order of one-tenth wavelength or less). The overall thickness of the whole structure is typically on the order of only 1/32 inch.
The shaped conductive surfaces include a microstrip radiator 1 and a connected transmission line 2 which terminate in a first connection pad or area 20 to which an output element of the three-element active device 5 (e.g., the collector terminal of a bipolar junction transistor) is physically and electrically connected (e.g., as by soldering).
The shaped conductive surfaces also include a second connection pad or area 22 within surface 7 to which a second element (e.g., the emitter of a bipolar junction transistor) of the three-element active device 5 is physically and electrically connected (e.g., by soldering).
In the exemplary embodiment, the three-element active device 5 may be an HP HXTR 4104 bipolar junction transistor pre-packaged in a ceramic holder with collector and emitter element connections extending on opposite sides to connection pads 20 and 22 as already described. In such an exemplary embodiment, the third element (e.g, the base of a bipolar junction transistor) is actually provided with a pair of (electrically common) connection areas extending on the other opposing sides of the packaged active device 5 so as to be physically and electrically connected (e.g., by soldering) to third connection pads 24a and 24b of the shaped single layer conductive surfaces 6 and 8, respectively, all as shown in FIG. 1. Thus, the surfaces 6 and 8 are, in reality electrically connected in parallel with each other at the single third element (e.g., the base electrode) of the three-element active device 5.
Shaped conductive surfaces 2, 6, 7 and 8 may be considered as separate lengths of microstrip feedline. The microstrip feedline 2 connects the microstrip antenna 1 as the r.f. load to the output element of the active device. The line segments 6 and 8 are r.f. shorted to the underlying ground plane 4 by plated-through holes (or rivets or the like) 26 and are of a relatively short length (e.g, less than one-eighth wavelength) so as to present an essentially inductive reactance to the third or base electrode of the active element 5. Line segment 7 is essentially open circuited with respect to r.f. at its outer edge and also relatively short so as to provide an essentially capacitive reactance to the second or emitter electrode of the active device 5.
The emitter and collector (or other) d.c. bias is provided to the active element through r.f. blocking filter circuits comprising quarter wavelength (at the intended operating frequency) microstrip transmission line segments 10, 12 and 9, 11. The narrow segments 9 and 10 have a relatively high r.f. impedance (e.g., on the order of 100 ohms) while the wider quarter wavelength segments 11 and 12 have a relatively lower r.f. impedance (e.g., on the order of 20-30 ohms). Since the two successive quarter wavelength sections together comprise a half wavelength transmission line open circuited at its outer end, they also present an essentially r.f. open circuit at their connection points to shaped surfaces 7 and 2 as will be apparent to those skilled in the art. The transition from high to low impedance line segments provides an easy way to locate the appropriate connection points for the emitter and collector bias sources as depicted in FIG. 1 while at the same time causing the higher impedance segments 9 and 10 to present a substantially inductive reactance as compared with the largely capacitive reactance presented by the more expansive low impedance quarter wavelength line segments 11 and 12.
The resultant lumped parameter equivalent electrical circuit network is depicted at FIG. 2 using the same reference numerals with respect to the corresponding lumped parameters. It will be seen that the bipolar junction transistor 5 is connected in a conventional common base oscillator circuit and that the r.f. load impedance for the active element 5 is provided directly and solely by the microstrip antenna 1 and the connected transmission line 11. The purely r.f. equivalent circuit is also depicted at FIG. 5. The capacitor 7 in this embodiment appears to have the most control over oscillator frequency and thus may be thought of as a "tuning" element that can be used in the design stage to primarily determine the final oscillator frequency--which is, of course, also affected by the inductances 6, 8 and by the resonant frequency of the microstrip antenna 1.
A two-step process was used to design the exemplary oscillatenna of FIGS. 1, 2 and 5. First, a non-oscillating circuit was designed using the measured S-parameters of the active device (e.g. the HXTR 4101 transistor). A common base transistor configuration was selected based on the operating performance and the availability of measured small signal S-parameters. The output impedance of the circuit as a function of input power was then measured with a network analyzer in a device line test system of conventional design and in accordance with the oscillator design principles explained in the earlier referenced published articles. When the reflected power minus the input power (i.e., the added power) at the output port of the test circuit reaches a maximum value, the output impedance is noted. This measured output impedance at the maximum added power point should be negative as a result of a reflection coefficient greater than unity within the circuit. In the exemplary embodiment, the maximum added power was approximately 18 dBm--which also represents the output power which can be achieved from the oscillator when it is matched to a load impedance equal to the negative of the thusly measured output impedance (again all in accordance with conventional device-line or load-pull oscillator design techniques). In the exemplary embodiment, the required load impedance of 75 -j100 ohms and was obtained directly by interchanging the test and reference arms on the network analyzer (in accordance with the direct device line measurement technique described in Hewlett-Packard Application Note 95-1 earlier referenced). On the other hand, if the test circuit had initially produced oscillations at or near the design frequency, the load-pull measurement technique of the earlier referenced Poulin article could have been used to determine the optimum load impedance rather than the device line measurement technique typically used for a non-oscillating circuit. Accordingly, the first step of the design process is strictly in accordance with conventional oscillator design techniques.
However, in the second step of the design process, rather than transforming the oscillator output impedance to 50 ohms with a matching network, similarly transforming the microstrip antenna to 50 ohms and interconnecting the thus matched antenna and output impedance with a 50 ohm transmission line, a microstrip antenna and feedline are used in this exemplary embodiment to directly provide the r.f. load impedance for the oscillator circuit. Using a microstrip antenna, it is possible to obtain the requisite load impedance to produce maximum power output from the active device and into the antenna structure where it can be radiated. In this way, the overall efficiency of the oscillatenna may be greatly enhanced.
This desired result is made possible, for example, because a dual-slotted microstrip antenna typically provides input resistance at resonance in the relatively high range of 250-300 ohms or so. This relatively high antenna input resistance can then be transformed to the desired predetermined load impedance for maximum added power in the oscillator design by adding a feedline of appropriate length. In essence, the feedline length can now be optimized to obtain maximum radiated power.
In an experimental version of the exemplary embodiment of FIG. 1, the microstrip radiator 1 was formed from an approximately 1.0"×1.0" conductive adhesive patch which could thus be moved to successive different positions along the preprinted microstrip transmission line 2. The resulting experimental data depicted below at Table I shows that maximum effective radiated power of 24.4 dBm EIRP was obtained at 3.5 GHz using a d.c. input power of only 450 milliwatts.
TABLE I______________________________________OSCILLATENNA FREQUENCY AND RADIATEDPOWER AS A FUNCTION OF FEEDLINE LENGTHFeedline EffectiveLength Frequency Radiated Power______________________________________0.7 inch 3.75 GHz 22.0 dBm0.9 inch 3.60 GHz 23.7 dBm1.0 inch 3.60 GHz 21.4 dBm1.1 inches 3.5 GHz 24.4 dBm1.15 inches 3.45 GHz 23.2 dBm1.2 inches 3.38 GHz 21.1 dBm______________________________________
A Smith Chart is depicted at FIG. 3 to show how the length of feedline 2 effectively rotates be 200 ohm edge impedance of microstrip radiator 1 to the requisite 75-j100 ohm load impedance required for the optimum design load impedance of the oscillator.
To again briefly summarize, the overall oscillator design procedure is generally known in the art and described in detail in the earlier cited references. The active device to be used is typically situated in a non-oscillatory circuit and its output impedance is measured as a function of input power. The output impedance noted at the maximum added power condition is then replaced by the negative of the noted output impedance to obtain maximum oscillator efficiency.
This invention now permits this known design technique to be applied to three element active device oscillatennas where a solid-state three-element active device is soldered or otherwise integrated onto or into a single layer of "printed" conductive surfaces which comprise the antenna radiator together with associated feedlines, oscillator r.f. resonant and d.c. biasing circuits all formed on one side of the dielectric sheet opposite a ground or reference plane provided on the other side of the sheet so as to result in a thin, lightweight, conformal and efficient oscillatenna assembly.
This result is achieved by suitably tailoring (e.g., proper width, length), a microstrip radiator 1 and its associated microstrip transmission line which are chosen so as to provide the predetermined requisite r.f. load impedance for the oscillator circuit. In particular, one does not transform the desired load impedance to match a standard transmission line value (e.g., 50 ohms) which is, at its other end, also matched to the antenna impedance. Rather, the desired load impedance for the oscillator is directly provided by the microstrip antenna and its associated transmission line.
Quarter wavelength high and low impedance transmission line segments are used to create d.c. bias feeding networks that are isolated from the higher r.f. output frequencies. Other shaped conductive surfaces are also included to provide the requisite reactive impedances which typically act in concert with the output load to form a resonant oscillator circuit with the three-element active device.
The oscillatenna embodiment depicted at FIG. 4 is quite similar to that depicted in FIG. 1. However, it will be observed that the transmission line 2 is considerably shorter and that its connection point with the microstrip radiator 1 is at a notch or indented area so as to select a slightly lower input impedance point on the microstrip radiator 1. In effect, the transmission line 2 of the FIG. 1 embodiment is approximately one-half wavelength longer than necessary so as to provide sufficient space to permit the experimental changing of the feedline length as reported above in Table I. A considerably shorter length transmission line 2 may be used to transform to the desired oscillator load impedance--even if one must start with a somewhat lower antenna input impedance (e.g. by using a notched connection area).
As depicted in FIG. 4, the integrated oscillator/microstrip antenna system (oscillatenna) includes a half wave (dual radiating slots) microstrip antenna element 1 and a microstrip/three-element active device oscillator connected directly to the antenna element 1 via a transmission feedline 2. As in the earlier embodiment, the oscillatenna of FIG. 4 is fabricated on a dielectric substrate 3 which has a conducting ground plane 4 on its other side.
Mutiple antenna elements formed in an array (e.g., an array of square, rectangular, circular or other geometrically-shaped microstrip radiators) with corporate, series or other transmission line feed networks may be used to obtain desired radiation patterns while still providing virtually any desired oscillator load impedance. In effect, the microstrip antenna element(s) and associated feedline structure(s) complete the oscillator and directly provide the required load impedance for oscillation of the active element at maximum efficiency.
The oscillatenna circuit includes a three-element active device 5 (e.g., a bipolar or GaAs FET transistor), reactive r.f. impedance oscillator circuitry (e.g., capacitance 7 and inductors 6, 8) together with appropriate bias connection circuitry formed from quarter wavelength high impedance transmission line segments 9 and 10 and quarter wavelength low impedance transmission line segments 11 and 12. Plated-through holes 26 may typically be used to obtain inductive reactance from relatively short elements 6 and 8 as should be appreciated by those in the art.
As with the earlier embodiment, the oscillator circuitry exclusive of the antenna and its associated transmission line load impedance is first designed using device S-parameters measured at the desired frequency of oscillation. Then using device line or load-pull measuring techniques (e.g., as described in the above-referenced articles by Wagner or Poulin), a load impedance corresponding to the maximum added power at the desired frequency of oscillation is determined in accordance with conventional oscillator design techniques. The maximum added power represents the power output expected from the completed oscillator if the load impedance is replaced by the negative of the thus measured output impedance at maximum added power conditions. A microstrip antenna 1 and its associated microstrip feedline 2 are then designed to provide this predetermined requisite load impedance directly to the output terminal of the three-element active device 5. The radiated frequency and power can be varied somewhat by changing the antenna patch and feedline size and can be optimized for maximum output power, for example, by modifying the feedline impedance and/or length--as earlier explained in connection with the embodiment of FIG. 1.
If the design procedure of Hewlett-Packard Application Note 975 is to be utilized, the design of an oscillatenna in accordance with this invention can be summarized as follows:
(1) The transistor is placed in a non-oscillating microstrip circuit (e.g. of the FIGS. 1 or 4 type but without the microstrip antenna 1 and associated feedline 2, see FIG. 2 of Hewlett-Packard Application Note 975).
(2) The output impedance of this non-oscillating circuit is measured as a function of input power.
(3) At each power level the reflected power is recorded.
(4) The incident power is subtracted from the reflected power to provide added power data at each power level.
(5) The circuit output impedance is measured at the power level corresponding to maximum added power.
(6) By reversing the reference and test arms on the network analyzer, the reflection coefficient (which is greater than 1) will be inverted and will now lie inside the standard Smith Chart (outer circle of the Smith Chart corresponds to a reflection coefficient of one). This is then the negative of the impedance displayed before reversing the network analyzer arms. It is this thus determined impedance that must be connected as a load to complete the optimized oscillator circuit.
(7) Rather than matching this predetermined impedance to 50 ohms (as would conventionally be done when designing just an oscillator), this predetermined impedance is provided directly by a microstrip antenna patch and its associated microstrip feedline (more than one patch and corporate or series feed network can also be utilized as should be appreciated).
(8) By combining the microstrip antenna/microstrip feedline and partial oscillator circuit characterized above, an oscillatenna results with maximum power at the design frequency.
A square one-half wavelength microstrip radiator patch produces an edge impedance (resistance) at resonance of about 250-300 ohms. Often this will be an impedance which can be used directly through the transmission line to provide the requisite oscillator load impedance, thus no modifications to the patch antenna may be necessary in some situations (e.g., such as indenting the feedline into the patch to reduce the starting impedance at the antenna input).
By adding one-half wavelength to the transmission line length TLL in an experimental prototype, th eline length is more practical for testing the optimum patch placement. A 0.95"×1.0" patch was used initially and the patch design equations are: ##EQU1##
As should be appreciated, other than common base junction transistor oscillator circuits can also be employed. For example, a typical common gate oscillator circuit (self-biased) as depicted in FIG. 6 is another quite feasible oscillatenna embodiment which is especially preferred for higher frequency operation. Other basic oscillator circuits may also be preferred for particular applications as well be appreciated by those in the art.
Although only a few specific exemplary embodiments of this invention have been described in detail above, those skilled in the art will appreciate that there are many possible modifications and variations which may be made in these exemplary embodiments while still retaining many of the novel features and advantages of this invention. Accordingly, all such variations and modifications are intended to be included within the scope of the appended claims.
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|U.S. Classification||455/129, 331/107.00R, 331/117.00D, 343/862, 455/124, 343/700.0MS|
|International Classification||H03B5/18, H04B1/04, H01Q1/24, H01Q9/04|
|Cooperative Classification||H01Q9/0407, H04B1/0458, H03B5/1847, H03B5/1852, H01Q1/247|
|European Classification||H01Q9/04B, H04B1/04C, H01Q1/24D, H03B5/18F1|
|Sep 15, 1983||AS||Assignment|
Owner name: BALL CORPORATION 47302 345 SOUTH HIGH ST MUNCIE IN
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:HIRSCH, VINCENT A.;REEL/FRAME:004176/0747
Effective date: 19830913
Owner name: BALL CORPORATION, A CORP OF IN, INDIANA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:HIRSCH, VINCENT A.;REEL/FRAME:004176/0747
Effective date: 19830913
|Sep 23, 1991||FPAY||Fee payment|
Year of fee payment: 4
|Nov 14, 1995||REMI||Maintenance fee reminder mailed|
|Apr 7, 1996||LAPS||Lapse for failure to pay maintenance fees|
|Jun 18, 1996||FP||Expired due to failure to pay maintenance fee|
Effective date: 19960410